The Reliance standard condensing gas tankless water heater delivers robust, on-demand performance and the flexibility to install in practically any residential setting. Optional X3 Scale Prevention Technology; Warranty exclusions apply. Features a built-in control display for settings and checking heater status or error codes. Manage temperature settings and activate the heater. Energy Star certified and extremely efficient with a Uniform Energy Factor of 0.95. Also complies with Ultra-Low NOx regulations. natural gas. can be installed indoors or outdoors with an outdoor vent cap kit (sold separately). 15-year Limited warranty on heat exchanger, 5-year limited warranty on parts